1. Field
Some example embodiments may relate generally to light modulators and/or digital exposure apparatuses including the same. Some example embodiments may relate generally to electroabsorption-type light modulators and/or digital exposure apparatuses including the same.
2. Description of Related Art
Generally, a method of forming a pattern on a substrate in a process of forming various flat panels for display such as a liquid crystal display (LCD) or an organic light emitting display (OLED), may be as follows: first, a pattern material is applied on a substrate, and selective exposure is performed on the pattern material by using a photomask, and then, pattern material parts having altered chemical properties or the other parts are removed selectively to thus form a pattern.
A digital exposure apparatus capable of forming a pattern on a substrate without using a photomask may have been developed according to gradual substrate enlargement and pattern refinement.
Such a digital exposure apparatus may have been suggested to solve the cost problem of lithography using existing expensive photomasks. The digital exposure apparatus may employ techniques of forming intended patterns by using light modulators, wherein pixels capable of changing their transmission or reflection of light are arranged and controlled in the light modulators, unlike using a photomask, which blocks light to certain pixels by using, for example, chromium (Cr) on a quartz substrate.
That is, the digital exposure apparatus may form patterns by using methods of irradiating light beams onto substrates, with pattern information formed of electrical signals, by using light modulators. The light modulators may be digital micro-mirror devices (DMDs), for example. The DMDs may include a plurality of micro mirrors that send light incident with a certain angles at a desired angle, and send the other light at different angles, to thus form a pattern on an exposed surface by using only necessary light.
Light modulators using DMDs may have very slow response speeds of several hundred hertz (Hz) to several hundred kilohertz (kHz) and, so, it may be difficult to secure a take time required for mass production. Also, pixel sizes of such light modulators may only be in the tens of μm and, thus, have limitations in terms of realizing high resolutions.